Doctors at four European universities have managed to perform the first trachea transplant operation using adult stem cells. The operation, done at Hospital Clinic in Barcelona, was successful and was detailed in Wednesday edition of British medical journal The Lancet. The organ transplant operation was the first to use stem cells in transplanting an airway.

The success of the operation raises hope that transplanting other organs may be possible one day without drugs to dampen the immune system, doctors said. They believe that “this first experience represents a milestone in medicine and hope that it will unlock the door for safe and recipient-tailored transplantation of the airway in adults and children.”

The patient, a 30-year-old woman from Colombia, had been suffering from tuberculosis for years. Claudia Castillo was hospitalized in March because her left bronchus was badly damaged by tuberculosis and she was unable to walk more than a few steps at a time, a statement from Bristol University reads.

Preparing for the transplant involved international collaboration and weeks of work. After finding a donor, the doctors first depleted the transplanted trachea of the donor's cells and then obtained bone marrow stem cells from the patient and grew them into cartilage cells. The doctors took adult stem cells and other stem cells from the healthy right airway of the patient and used the samples to create millions of cartilage and tissue cells; they used stem cells from the patient’s bone marrow because these cells have the ability to transform into different types of tissue. Since they use the patient’s own stem cells, her body accepted the organ transplant without the use of immune-suppressant drugs. The team created a hybrid organ in a lab; this procedure helped the patient’s body identify the organ as its own and make immunosuppressant drugs unnecessary.

“The probability this lady will have a rejection is almost zero percent,” Dr. Paolo Macchiarini, head of thoracic surgery at the Hospital Clinic, Barcelona who performed the transplant, told a news conference. The patient has not developed antibodies to her graft, despite the fact that she hasn’t taken immunosuppressive drugs.

Four months after the surgery, the woman is enjoying a normal life with no signs of rejection, doctors said. The quality of life has improved. Dr. Paolo Macchiarini and his colleagues said in a news release that the woman was still doing well four months after surgery, being able to “walk up two flights of stairs, walk 500 meters without stopping, and care for her children.” “We are terribly excited by these results,” Macchiarini was quoted as saying by WebMD Health News.

Martin Birchall, a professor at the Bristol University said the transplant “showed the very real potential for adult stem cells and tissue engineering to radically improve their ability to treat patients with serious diseases.”